Electronic and optical properties of g-C3N4/MoS2 modulated via biaxial strain and external electric field.

Two-dimensional materials such as graphitic carbon nitride (g-C3N4) and molybdenum disulfide (MoS2) have attracted considerable interest for optoelectronic and photocatalytic applications owing to their unique electronic structures and favorable optical characteristics. However, the performance of a single material is often constrained by inherent limitations in bandgap tunability and insufficient light absorption efficiency. In this study, a g-C3N4/MoS2 van der Waals heterostructure is constructed and its electronic and optical properties under biaxial strain and external electric field are systematically investigated using first-principles calculations. The results indicate that the g-C3N4/MoS2 heterostructure exhibits excellent stability and tunable optoelectronic properties under biaxial strain and external electric fields. Specifically, the bandgap of the g-C3N4/MoS2 heterostructure reaches its maximum value under a compressive strain of -4%, and tensile strain induced a red shift in the absorption edge and enhanced light absorption. In addition, the external electric field exhibits a relatively weak modulation effect on the bandgap of the g-C3N4/MoS2 heterojunction. Also, a new absorption peak emerges under the influence of the electric field, which enhances visible light absorption. Moreover, it's found that the synergistic effect of strain and electric field for g-C3N4/MoS2 offers distinct advantages over their individual application. The significant reduction of the bandgap facilitates photogenerated carrier migration, while the redshift of the absorption edge, accompanied by the emergence of a new absorption peak, enhances the light absorption capability. This study paves the way for designing tunable, high-performance optoelectronic and photocatalytic devices, demonstrating the promising potential of the g-C3N4/MoS2 heterostructure for practical applications in energy and information technologies.